A size of paper produced by folding a printing sheet four times to form sixteen leaves; a page of this size, or a book composed of such pages; compare "sexto-decimo". Usually abbreviated 16mo. In early use frequently figurative: a small person or thing.
Late 16th century; earliest use found in John Lyly (1554–1606), writer and playwright. Alteration of post-classical Latin sexto decimo sexto-decimo.